Sometimes CMPA is confused with lactose intolerance, but they are very different: lactose intolerance is the inability to digest the lactose sugar and does not involve the body’s immune system. However, the two share some signs and symptoms, such as stomach and gut problems (like wind and diarrhea).
During infancy, lactose accounts for most of the dietary carbohydrates. Lactose is a disaccharide present in dairy products. The concentration of lactose in mother’s milk is 7.2 mg/100 ml whereas in a cow’s milk it reaches only 4.7 mg/100 ml. In order to be digested and absorbed, lactose requires the presence of lactase, an enzyme found in the small intestine. Lactose digestion in the premature neonate may be incomplete in the small intestine but partially salvaged from the colon. Lactase levels decline from a peak at birth to less than 10% of the pre-weaning infantile level in childhood.
Treatment is a lactose free or lactose poor diet. Lactose free is only needed in the rare infants with congenital lactase deficiency. In all the other clinical situations, some lactase activity will persist and thus small amounts of lactose are tolerated.